Small claims court. Which will probably cost you more than the cost of the item, and definitely will take long enough for the fraudster to disappear with your money.
You would have no basis to request a reversal of a Zelle transfer, because when you make a Zelle transfer you have to agree to treat the payment as a gift not as a payment for goods. Failure to deliver the goods is not any concern of Zelle or the banks participating in using Zelle for transfers.